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optical coupler

  1. Optocouplers are optical couplers that galvanically isolate signals from each other and couple light energy bidirectionally between several optical fibers. They are used in electronic circuits, in measurement technology, in field buses, data transmission systemsor in production technology where they provide galvanic potential separation. The coupler type has a decisive influence on the modes, whereby only multimode fibers, i.e. the step fiber and the gradient fiber, are used for coupler mechanisms. There are coupler types without mode dependence, but also those with strong dependence. The coupler types are divided into star couplers and taper couplers, and couplers with offset, bifurcated, core-bevelled, core-fused and beam- splitter principles, as well as couplers with gradient lenses.
    Biconical taper

    Biconical taper

    coupler The most important parameter for optocouplers is the insertion loss, which is generally between 0.5 dB and 1 dB. An exception are couplers based on the offset principle and the taper principle, which have values between 2 dB and 3.5 dB.
  2. Optocouplers are electronic assemblies that usually contain both an E/O converter and an O/E converter and are housed in a common package. In such an assembly, the combination light-emitting diode/ photodiode forms the actual coupling element. The light-emitting diode converts the electrical signal into a light signal, and the photodiode converts the light signal sent by the light-emitting diode back into an electrical signal. This arrangement - electrical, optical, electrical - provides galvanic isolation between the transmitting and receiving sides.
    3-dB coupler for polymer fibers, photo:

    3-dB coupler for polymer fibers, photo:

    Since high-speed communication requires high transmission rates and good timing with only minor changes in transit times, pulse width distortions, etc., optocoupler technology is increasingly reaching its limits. Magnetic couplers, transformer-based couplers and capacitive couplers are available as alternatives.
Englisch: optical coupler
Updated at: 28.06.2019
#Words: 280
Links: light, fibers, measurement, field, data transmission
Translations: DE

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